Dielectrophoretic separation of metallic arc-discharge single-walled carbon nanotubes in a microfluidic channel

Electronic type-dependent separation of single-walled carbon nanotubes (SWNTs), preserving pristine crystallinity and length, is of great interest since mixtures of semiconducting and metallic species are produced by current synthesis methods. Here we separated highly-enriched metallic SWNTs, synthesized by the arc-discharge method, by dielectrophoresis in a microfluidic channel. The design of microelectrodes was optimized to prevent the nanotube deposition on the electrodes for prolonged operation of the microfluidic chip. The average length of separated highly crystalline metallic SWNTs was relatively long (2–2.4 μm).